Don’t Drink the Water … In Lake Erie

A Harmful Algal Bloom in Lake Erie from 2013. Ohio Sea Grant

It’s the stuff dystopian sci-fi is made of: A city on the edge of the largest fresh water reserve on the planet suddenly has no drinkable water. At 1:21 am Saturday morning, the City of Toledo put out an alert: don’t drink or bathe in water from the city water supply. About 500,000 residents of the region were affected. Including me.

Lake Erie’s mess helped inspire the formation of the EPA in 1970, and the Clean Water Act of 1972. Things got better; Lake Erie became a hub for fishing and recreation, and is considered the “Walleye Capitol of the World.” To be able to consume fish from the lake at all, much less swim in the water, is a major achievement in just a few decades.

How did Lake Erie go from polluted, flaming disaster to environmental success story…and then back again to environmental disaster, in just 45 years? And why is it always Lake Erie that has issues? The answers to that question are not hard to find.

“The science about the algae is very clear. The policy decisions to fix it … less so.”
—Dr. Chris Mayer, University of Toledo Lake Erie Center.

Lake Erie is different from the other Great Lakes because it’s so shallow. The western end of the lake (where Toledo is) has an average depth of only 24 feet. The water warms quickly, and it’s a great place to live if you’re a blue-green algae (cyanobacteria). Say, toxin-producing Microcystis. Microcystis has the ability to control its buoyancy; it can sink or rise to the top of the water at will to chase the sunlight.

This satellite overview shows the water surface temperature in the shallow west end of Lake Erie. It gets warm. (Cloud obscuring part of area in white) AVHRR image; NOAA

When you look at the satellite photo below of the cyanobacterial bloom, it’s a pretty close overlay for the warm western shallow section of the lake. And exactly where the water intake for the Toledo Water Treatment plant is (red marker on map). The satellite image here is from July 31st, 2014; the problem with toxic algae was not a surprise overnight development.

The location of the Toledo Municipal Water Intake in Lake Erie; right in the middle of the algal bloom. Inset is MODIS Aqua Cyanobacterial Index from July 31, 2014; the day Toledo water tested positive for microcystins. The threshold for cyanobacteria detection is 35,000 cells/ml. NOAA + Google Maps Overlay

Both scientists and politicians know there is a problem with algae at this end of the lake nearly every year; look at this satellite photo from 2013. Or 2012. But it’s not just bad luck and geology; there is a third piece in the Lake Erie Algal Bloom equation.

Phosphorus and the Maumee Watershed

The Maumee River was key to Toledo’s early economic success; it’s also the cause of algal bloom problems now. Maumee is the largest watershed in the Great Lakes system. It runs right through the Breadbasket of the Midwest, an intensively farmed area. Satellite views show thousands upon thousands of little boxes of green; the highly productive farms and fields of Ohio, Michigan, and Indiana.

The Maumee watershed is such productive farmland because it was once a swamp; the Great Black Swamp. Drainage tiles allowed removal of water from the surface of the soil, and made wonderfully rich swampland available for farming. Drainage tiles also collect up runoff and deliver it very efficiently to streams and rivers.

Algal blooms are not new to Lake Erie; they happened in the 60s and 70s too. Then the blooms were fueled by runoff from sewer overflows and poorly treated wastewater. The Clean Water Act helped provide funding and motivation to clean up the lake; while storm sewer overflows still happen, the tonnage of phosphorous flowing into Lake Erie was successfully reduced by nearly 60 percent in the last 40 years. But then algal blooms came back.

The problem is not as simple as “bad farmers”; farming best practices actually use fertilizer highly efficiently. Only about 2 percent of applied fertilizer is lost. The problem is volume; that many farms, golf courses, and suburban lawn owners applying fertilizer adds up, even if only a small amount washes off each allotment.

Chemistry plays a role as well; changes in the type of fertilizers sold make them more soluble (“bio-available“), and easier for plants (including algae) to take up and use. So while the total tonnage of phosphorous entering the lake is much smaller, the problem of too much phosphorous persists.

Weather is not Helping

Is global climate change a contributor to the problem of algal blooms? Evidence says yes, but it’s not warmer temperatures that are the problem–Microcystis produces toxins even when water is fairly cool. It’s extreme weather that creates blooms.

“This is very early to have problems in Toledo; the bloom is likely to persist along the Erie shoreline until October. Blooms typically reach greatest severity in September…. Most of the blue-greens float, so if winds blow out of the northeast, that will blow the bloom right back into Maumee Bay.”

Empty Shelves in my Local Grocery store. No water to be purchased. Gwen Pearson

Looks like I need to keep all my extra bottled water close at hand.

If we have all this data, why isn’t anyone fixing the problem?

Amassing evidence doesn’t seem to be enough to create public policy change. A comprehensive overview of the issue compiled by an international scientific committee was published in February 2014. It represents years of research by the large and vibrant science community studying the Great Lakes.

Reutter served as Co-Chair for one of the sub-groups on that task-force; his group recommended reducing the amount of phosphorus flowing into the lake by 40 percent. That seems like a lot, but he pointed out that the amount of Phosphorus has already been reduced by 60 percent since the 1960s.

Municipal sewers are identifiable point sources of pollution; the problem now is thousands of individual farm and lawn owners. Mechanisms and laws for regulating point-source pollution, like sewer overflows, exist. A way to regulate the actions of millions of individual land owners… not so much.

Urban sources represent about 20 percent of total basin Phosphorus input. Urban loading comes from storm water runoff, lawns and gardens, and pet waste. Reutter suggested that that rather than blaming farmers, everyone can play a part:

“We all ought to be doing things to put less phosphorous in the system. We can be careful with cleaners we use, keep water on our property, make sure our septic tanks work well, and be willing to pay for sewer improvements. The bottom line is there is something here for all of us to do.

We need to encourage farmers to take action, but we can’t simply say ‘you guys have to solve the problem for us.’ Frankly I think we would be more likely to get action from farmers if they could see everyone else taking steps to help.”

Will the Toledo water crisis provide enough motivation for new regulations on fertilizer use? A few practices, such as manure spreading on frozen ground, are known to cause increased runoff, and should probably be banned. That’s about the only easy target; the rest of the solutions are going to both cost money and inconvenience people.